Electrode manufacturing apparatus for lithium ion capacitor and electrode manufacturing method therefor

ABSTRACT

A time for doping an electrode material on an electrode sheet with a lithium ion can be reduced. The electrode manufacturing apparatus includes a processing chamber  200  to and from which the electrode sheet is loaded and unloaded; a rare gas supply unit  230  configured to introduce a rare gas into the processing chamber; an exhaust device  220  configured to exhaust an inside of the processing chamber to a certain vacuum level; and a lithium thermal spraying unit  210  configured to dope a carbon material C with the lithium ion by forming a lithium thin film on the carbon material of the electrode sheet W loaded into the processing chamber while melting and spraying lithium-containing powder.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Japanese Patent Application No.2012-279685 filed on Dec. 21, 2012, the entire disclosures of which areincorporated herein by reference.

TECHNICAL FIELD

The embodiment described herein pertains generally to an electrodemanufacturing apparatus for a lithium ion capacitor and an electrodemanufacturing method for a lithium ion capacitor.

BACKGROUND

A process for manufacturing an electrode for a lithium ion capacitorsuch as a lithium ion secondary battery includes a pre-doping process inwhich an electrode material is doped in advance with a lithium ion. Byway of example, when a negative electrode (anode) of a lithium ionsecondary battery is manufactured, a carbon material such as activatedcarbon used as an electrode material is doped with a lithium ion.

Conventionally, in such a lithium ion doping process, a carbon materialis immersed in a doping tank filled with an electrolyte containing alithium ion to be doped with the lithium ion (see, for example, PatentDocument 1).

Patent Document 1: Japanese Patent Laid-open Publication No. H09-022690

However, in the conventional lithium ion doping process, it takes a longtime, e.g., several days, to uniformly dope the entire carbon materialwith the lithium ion. Due to a long time for the conventional lithiumion doping process, the production efficiency of a lithium ion capacitoris reduced.

SUMMARY

In view of the foregoing problems, an example embodiment provides anelectrode manufacturing apparatus which can greatly reduce a time fordoping an electrode material with a lithium ion.

In one example embodiment, an apparatus of manufacturing an electrodefor a lithium ion capacitor by doping an electrode material (e.g., acarbon material) on an electrode sheet with a lithium ion includes aprocessing chamber to and from which the electrode sheet is loaded andunloaded; a rare gas supply unit configured to introduce a rare gas intothe processing chamber; an exhaust device configured to exhaust aninside of the processing chamber to a preset vacuum level; and a lithiumthermal spraying unit configured to dope the electrode material with thelithium ion by forming a lithium thin film on the electrode material ofthe electrode sheet loaded into the processing chamber while melting andspraying lithium-containing powder.

The lithium thermal spraying unit may include a lithium-containingpowder supply unit configured to discharge the lithium-containing powdertoward the electrode material of the electrode sheet; and at least oneheating gas supply unit configured to supply a heating gas that meltsthe lithium-containing powder discharged from the lithium-containingpowder supply unit.

The lithium-containing powder supply unit may be providedperpendicularly to the electrode material, and the at least one heatinggas supply unit may be arranged to be inclined to the lithium-containingpowder supply unit such that the heating gas is discharged toward aspace between a powder discharge opening of the lithium-containingpowder supply unit and the electrode material.

The electrode sheet may be formed in a roll shape, and accommodationchambers configured to accommodate the electrode sheet may berespectively provided at both sides of the processing chamber to becommunicated with each other. Further, the electrode sheet may beunwound in one of the accommodation chambers to pass through theprocessing chamber, and then, may be wound in the other accommodationchamber. Furthermore, the lithium thermal spraying unit may form thelithium thin film on the electrode material while the electrode sheet isunwound and passes through the processing chamber.

The lithium-containing powder supply unit may be a substantiallyplate-shaped member in which multiple holes are formed, and theplate-shaped member may be extended in a width direction of theelectrode sheet and arranged perpendicularly to the electrode sheet.Further, the holes through which the lithium-containing powder issupplied may be arranged in the width direction of the electrode sheet.Furthermore, the at least one heating gas supply unit may be plural innumber, and two heating gas supply units may be arranged to besymmetrical with respect to each hole of the lithium-containing powdersupply unit in a longitudinal direction of the electrode sheet.

In another example embodiment, a method of manufacturing an electrodefor a lithium ion capacitor by doping an electrode material on anelectrode sheet with a lithium ion includes depressurizing an inside ofa processing chamber, to and from which the electrode sheet is loadedand unloaded, under a rare gas atmosphere; and doping the electrodematerial with the lithium ion by forming a lithium thin film on theelectrode material of the electrode sheet loaded into the processingchamber while melting and spraying lithium-containing powder.

According to the example embodiments, while melting and spraying thelithium-containing powder, the electrode material is doped with thelithium ion by forming the lithium thin film on the electrode materialof the electrode sheet loaded into the processing chamber under the raregas atmosphere. As a result, it is possible to greatly reduce a time fordoping the electrode material with the lithium ion. The foregoingsummary is illustrative only and is not intended to be in any waylimiting. In addition to the illustrative aspects, embodiments, andfeatures described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the detailed description that follows, embodiments are described asillustrations only since various changes and modifications will becomeapparent to those skilled in the art from the following detaileddescription. The use of the same reference numbers in different figuresindicates similar or identical items.

FIG. 1 is a cross sectional view illustrating a configuration example ofan electrode manufacturing apparatus in accordance with an exampleembodiment;

FIG. 2 is a top view of the electrode manufacturing apparatus of FIG. 1;

FIG. 3 is a cross sectional perspective view of a processing chamber ofFIG. 1 when taken along a line A-A of FIG. 2;

FIG. 4 is a flow chart illustrating an example of an electrodemanufacturing process in accordance with the example embodiment;

FIG. 5 is a cross sectional view for explaining a case where a hopperequipped with a shaker is provided at a lithium-containing powder supplyunit in accordance with the example embodiment;

FIG. 6 is a cross sectional view for explaining a case where a hopperequipped with a stirrer is provided at the lithium-containing powdersupply unit in accordance with the example embodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part of the description. In thedrawings, similar symbols typically identify similar components, unlesscontext dictates otherwise. Furthermore, unless otherwise noted, thedescription of each successive drawing may reference features from oneor more of the previous drawings to provide clearer context and a moresubstantive explanation of the current example. Still, the examplesdescribed in the detailed description, drawings, and claims are notmeant to be limiting. Other embodiments may be utilized, and otherchanges may be made, without departing from the spirit or scope of thesubject matter presented herein. It will be readily understood that theaspects of the present disclosure, as generally described herein andillustrated in the drawings, may be arranged, substituted, combined,separated, and designed in a wide variety of different configurations,all of which are explicitly contemplated herein.

(Configuration Example of Electrode Manufacturing Apparatus for LithiumIon Capacitor)

An apparatus of manufacturing an electrode for a lithium ion capacitor(hereinafter, referred to as “electrode manufacturing apparatus”) inaccordance with an example embodiment will be explained with referenceto the accompanying drawings. Herein, there will be exemplified anelectrode manufacturing apparatus (doping apparatus) configured toperform a process for doping an electrode material on an electrode sheetwith a lithium ion as a process for manufacturing a negative electrode(anode) used in a lithium ion capacitor such as a lithium ion secondarybattery.

FIG. 1 is a cross sectional view illustrating a schematic configurationof the electrode manufacturing apparatus in accordance with the presentexample embodiment. FIG. 2 is a top view of the electrode manufacturingapparatus of FIG. 1. FIG. 1 is a longitudinal cross sectional view takenalong a line A-A of FIG. 2. FIG. 3 is also a cross sectional perspectiveview of a processing chamber depicted in FIG. 1.

An electrode manufacturing apparatus 100 in accordance with the presentexample embodiment is configured to form a film on an electrode materialformed on a roll-shaped electrode sheet by thermal spraying of lithiumin a processing chamber while winding and unwinding the roll-shapedelectrode sheet. The processing chamber is in a rare gas atmospherewhile being evacuated. Thus, by forming a lithium thin film on theelectrode material by the thermal spraying of the lithium, the electrodematerial can be doped with a lithium ion. Herein, a carbon material suchas activated carbon will be exemplified as the electrode material of theelectrode sheet.

To be specific, as depicted in FIG. 1, the electrode manufacturingapparatus 100 in accordance with the present example embodiment includesan unwinding-side accommodation chamber 110A configured to accommodate aroll-shaped electrode sheet W therein, a winding-side accommodationchamber 110B provided away from the accommodation chamber 110A, and aprocessing chamber 200 provided between the accommodation chambers 110Aand 110B. Each of the accommodation chambers 110A and 110B, and theprocessing chamber 200 is formed of an airtight housing made of metalsuch as stainless steel or aluminum. Further, by way of example, anopening which can be blocked by a cover member or a door member may beformed at a front surface of each of the accommodation chambers 110A and110B to allow the electrode sheet W to be loaded or unloaded.

The processing chamber 200 and the unwinding-side accommodation chamber110A communicate with each other by a communication hole GA. Theroll-shaped electrode sheet W unwound in the unwinding-sideaccommodation chamber 110A is transferred into the processing chamber200 through the communication hole GA.

The processing chamber 200 and the winding-side accommodation chamber110B communicate with each other by a communication hole GB. Theelectrode sheet W processed in the processing chamber 200 is unloadedfrom the processing chamber 200 through the communication hole GB to thewinding-side accommodation chamber 110B to be wound in the winding-sideaccommodation chamber 110B. When the electrode sheet W processed asdescribed above is wound, a processing surface thereof may be coatedwith a resin (for example, a resin film) that is easily peeled off whilebeing wound.

Further, between the processing chamber 200 and the respectiveaccommodation chambers 110A and 110B, sealing members SA and SB, such asO-rings, surrounding the respective communication holes GA and GB areprovided to airtightly seal them.

The accommodation chambers 110A and 110B include exhaust openings 122Aand 122B connected to exhaust devices 120A and 120B that are configuredto exhaust insides of the accommodation chambers 110A and 110B,respectively. The processing chamber 200 includes an exhaust opening 222connected to an exhaust device 220 that is configured to exhaust aninside of the processing chamber 200. The exhaust devices 120A, 120B,and 220 may be formed of vacuum pumps, respectively, and providedseparately.

With the exhaust devices 120A, 120B, and 220, pressures inside theaccommodation chambers 110A and 110B, and the processing chamber 200 canbe adjusted separately and respectively. With such devices, there may begenerated a pressure difference between the accommodation chambers 110Aand 110B and the processing chamber 200. By way of example, in order tosuppress internal atmospheres of the respective accommodation chambers110A and 110B together with particles or the like from being introducedinto the processing chamber 200 through the communication holes GA andGB, pressures inside the accommodation chambers 110A and 110B may beadjusted to be lower than a pressure inside the processing chamber 200.Further, it is not necessary to separately provide the exhaust devices120A and 120B of the accommodation chambers 110A and 110B, and a singlecommon exhaust device may be provided.

The unwinding-side accommodation chamber 110A includes an unwindingshaft 112A, and the winding-side accommodation chamber 110B includes awinding shaft 112B. When the roll-shaped electrode sheet W is set on theunwinding shaft 112A, for example, a central portion of the roll-shapedelectrode sheet W is inserted into the unwinding shaft 112A to besupported.

The unwinding shaft 112A and the winding shaft 112B are rotatablysupported in the accommodation chambers 110A and 110B, respectively. Inthis case, each of the unwinding shaft 112A and the winding shaft 112Bmay be supported at one side thereof or both sides thereof. As depictedin FIG. 2, the unwinding shaft 112A and the winding shaft 112B arerespectively connected to motors 114A and 114B provided outside theaccommodation chambers 110A and 110B. The unwinding shaft 112A and thewinding shaft 112B are configured to be forwardly rotated or reversely(inversely) rotated by the motors 114A and 114B, respectively. Thus, theelectrode sheet W can be transferred in a transfer direction as indictedby an arrow of FIG. 1 in which the electrode sheet W is transferred fromthe unwinding shaft 112A to the winding shaft 112B. Further, theelectrode sheet W can also be transferred in the opposite direction tothe direction indicated by the arrow of FIG. 1, i.e. from the windingshaft 112B to the unwinding shaft 112A.

In the respective accommodation chambers 110A and 110B, guide rollers102A and 102B configured to transfer the electrode sheet W are provided.Further, in the processing chamber 200, guide rollers 202A and 202Bconfigured to transfer the electrode sheet W are provided at sides ofthe accommodation chambers 110A and 110B, respectively. The electrodesheet W set on the unwinding shaft 112A is extended to the winding shaft112B through the communication holes GA and GB via the multiple guiderollers 102A, 202A, 202B, and 102B. Further, the number and arrangementof the guide rollers are not limited thereto. In addition to the guiderollers, a tension roller configured to adjust tension of the electrodesheet W may be provided.

The processing chamber 200 includes a lithium thermal spraying unit 210at a ceiling portion thereof. The lithium thermal spraying unit 210 isconfigured to dope a carbon material C with a lithium ion by forming alithium thin film on the carbon material C as an electrode material ofthe electrode sheet W loaded into the processing chamber 200 whilemelting lithium-containing powder (lithium powder or the like).

As depicted in FIG. 3, the lithium thermal spraying unit 210 includes alithium-containing powder supply unit 250 configured to discharge andsupply the lithium-containing powder toward the carbon material C of theelectrode sheet W and a heating gas supply unit 260 configured to meltthe lithium-containing powder by supplying a heating gas (a rare gassuch as argon heated to a certain temperature) for melting thelithium-containing powder discharged from the lithium-containing powdersupply unit 250.

The lithium-containing powder supply unit 250 is a substantiallyplate-shaped member in which multiple holes 252 are formed. Theplate-shaped member is extended in a width direction of the electrodesheet W and arranged perpendicularly to the electrode sheet W. Further,the multiple holes 252 are formed in the plate-shaped member in alongitudinal direction (vertical direction) thereof, and thelithium-containing powder is supplied through the holes 252. Each of theholes 252 penetrates the lithium-containing powder supply unit 250 to alower end thereof, and the lithium-containing powder is dischargedthrough a powder discharge opening 254 at the lower end. At a sideportion of a base end of each hole 252, there is formed a gas inletopening 256 through which a rare gas, such as argon, serving as acarrier gas of the lithium-containing powder is introduced.

As depicted in FIG. 2, the multiple holes 252 are arranged to beequi-spaced from each other in the width direction of the electrodesheet W. Further, desirably, the number and arrangement of the holes 252may be determined such that a lithium thin film is continuously formedwithout being cut in the width direction of the carbon material (in adirection perpendicular to the transfer direction) of the electrodesheet W. Although, in FIG. 2, the lithium-containing powder supply unit250 including five holes 252 is exemplified, the number of the holes 252is not limited thereto and may be four or less or six or more.

With this configuration of the lithium-containing powder supply unit250, by introducing an argon gas through the gas inlet opening 256, thelithium-containing powder passing through the respective holes 252 isdischarged from the powder discharge opening 254 at the lower endthereof to be sprayed onto the carbon material C of the electrode sheetW. By controlling a flow rate of the argon gas introduced through thegas inlet opening 256, a discharge speed of the lithium-containingpowder can be adjusted.

Further, lithium contained in the lithium-containing powder is highlyreactive and easily ignitable. Therefore, a gas, which does not reactwith the lithium, such as a rare gas including an argon gas, is used asa carrier gas. Thus, it is possible to suppress spontaneous ignition ofthe lithium.

The heating gas supply unit 260 is formed in a substantially cylindershape as depicted in FIG. 3. The heating gas supply unit 260 depicted inFIG. 3 is configured by wrapping a heater 264 around a gas line 262through which a rare gas such as an argon gas passes. As depicted inFIG. 3, a base end of the gas line 262 is supported by a supportingmember 263 made of ceramic or the like, and a glass pipe 266 made ofquartz glass or the like may be provided at a front end side than thesupporting member 263. The gas line 262 may be arranged within the glasspipe 266. With this configuration, it is possible to stably maintain atemperature of the rare gas.

In the heating gas supply unit 260, when the heater 264 is turned on andthe rare gas is introduced from the base end of the gas line 262, therare gas passing through the gas line 262 is heated by the heater 264and the heated rare gas is discharged through a gas discharge opening268 at a front end of the gas line 262. Thus, by arranging the heatinggas supply unit 260 to supply the heated rare gas to thelithium-containing powder discharged through the powder dischargeopening 254 of the lithium-containing powder supply unit 250, thelithium-containing powder can be melted to be sprayed onto the carbonmaterial C of the electrode sheet W.

Herein, as the lithium-containing powder, for example, lithium metalpowder coated with a phosphorus-containing compound or the like may beused. Since this lithium metal powder is very stable in the air and thuseasy to handle. Further, by heating the lithium metal powder to atemperature higher than the melting point of lithium, the lithium metalpowder is melted and lithium is obtained. In the present exampleembodiment, since the lithium metal powder is heated with the heatinggas, the lithium can be sprayed onto the electrode material. Further,the lithium-containing powder is not limited thereto.

Desirably, the number and arrangement of the heating gas supply unit 260may be determined depending on the number and arrangement of the holes252 of the lithium-containing powder supply unit 250 as depicted in FIG.3. FIG. 3 illustrates an example where two heating gas supply units 260are provided with respect to one hole 252 of the lithium-containingpowder supply unit 250. To be specific, with respect to one hole 252 ofthe lithium-containing powder supply unit 250, two heating gas supplyunits 260 are arranged in a symmetrical manner on both sides of theelectrode sheet W in a longitudinal direction thereof.

In this case, two heating gas supply units 260 are arranged such that aheating gas from the heating gas supply units 260 can be suppliedbetween the powder discharge opening 254 of the hole 252 and the carbonmaterial C of the electrode sheet W. To be specific, two heating gassupply units 260 are arranged to be inclined at an acute angle to thelithium-containing powder supply unit 250 (hole 252).

With this configuration, the lithium-containing powder discharged fromthe powder discharge opening 254 of each hole 252 is heated with aheating gas to be melted. Thus, since the lithium is sprayed toward thecarbon material C of the electrode sheet W, a lithium thin film can beformed on carbon material C at a high speed. Thus, it is possible togreatly reduce a time for doping the carbon material C with a lithiumion.

However, since the lithium is highly reactive, if a lithium film isformed in the atmosphere (in the air), the lithium is highly likely tobe spontaneously ignited. In this regard, by spraying the lithium underthe rare gas atmosphere such as an argon gas, it is possible to form alithium film without being spontaneously ignited.

Therefore, in the electrode manufacturing apparatus 100 in accordancewith the present example embodiment, a rare gas supply unit is provided,and a rare gas is used as the carrier gas of the lithium-containingpowder supply unit 250 or the heating gas of the heating gas supply unit260. Further, the rare gas is also introduced into the processingchamber 200 and the respective accommodation chambers 110A and 1106communicating with the processing chamber 200, so that a lithium filmcan be formed under the rare gas atmosphere.

Hereinafter, a specific configuration example of the rare gas supplyunit will be explained with reference to the accompanying drawings. FIG.1 illustrates an example where a rare gas is introduced into each of theprocessing chamber 200 and the accommodation chambers 110A and 1106while a flow rate thereof is separately controlled. Further, asdescribed above, an argon gas may be used as the rare gas, but any raregas may be used.

As depicted in FIG. 1, the accommodation chambers 110A and 1106respectively include rare gas supply units 130A and 130B configured tosupply a rare gas (herein, an argon gas). The rare gas supply units 130Aand 130B include rare gas supply sources 132A and 132B, respectively.The rare gas supply sources 132A and 132B are respectively connected togas inlet openings 133A and 133B of the accommodation chambers 110A and1106 via lines 134A and 134B.

The lines 134A and 134B respectively include mass flow controllers (MFC)135A and 135B as flow rate controllers configured to control flow ratesof rare gases and opening/closing valves 136A and 136B.

The processing chamber 200 includes a rare gas supply unit 230configured to supply a rare gas (herein, an argon gas). The rare gassupply unit 230 includes a rare gas supply source 232. The rare gassupply source 232 is connected to a gas inlet opening 233 of theprocessing chamber 200 via a line 234 and connected to the gas inletopening 256 of the lithium-containing powder supply unit 250 via a line237. Further, the rare gas supply source 232 is also connected to gaslines 262 of the respective heating gas supply units 260 via a line 238and multiple branch lines 239 branched from the line 238.

The lines 234, 237, and 238 respectively include mass flow controllers(MFC) 235 as flow rate controllers configured to control flow rates ofrare gases and opening/closing valves 236. With this configuration, flowrates of rare gases to be supplied into the processing chamber 200, thelithium-containing powder supply unit 250, and the heating gas supplyunit 260 can be controlled separately.

Further, in the present example embodiment, there has been explained acase where the rare gas supply sources 132A, 132B, and 232 are providedseparately, but the example embodiment is not limited thereto. If thesame kind of rare gases are used, a single common rare gas supply sourcemay be provided at the processing chamber 200 and the accommodationchambers 110A and 110B. Further, a flow rate controller configured tocontrol a flow rate of a rare gas is not limited to a mass flowcontroller (MFC).

As depicted in FIG. 1, the electrode manufacturing apparatus 100includes a control unit 300 configured to control the respectivecomponents thereof. The control unit 300 is connected to a manipulationunit 310 implemented as a keyboard or a display through which anoperator inputs commands to manipulate the electrode manufacturingapparatus 100. The manipulation unit 310 may be implemented as a touchpanel.

Further, the control unit 300 is connected to a storage unit 320configured to store a program for performing an electrode manufacturingprocess to be described later in the electrode manufacturing apparatus100 under the control of the control unit 300, recipe data (for example,preset pressures inside the processing chamber 200 and the accommodationchambers 110A and 110B, a winding speed of the electrode sheet W, andthe like) required to execute the program, and the like.

Furthermore, such recipes may be stored in a hard disc or asemiconductor memory, or may be set in a preset area of the storage unit320 while being stored in a storage medium readable by a portablecomputer such as a CD-ROM or a DVD.

The control unit 300 reads out a desired process recipe from the storageunit 320 in response to an instruction from the manipulation unit 310and controls each component, so that a desired process is carried out inthe electrode manufacturing apparatus 100. Further, the recipes can bechanged by the manipulation unit 310.

(Roll-Shaped Electrode Sheet)

Hereinafter, there will be explained a roll-shaped electrode sheet to beused in a doping process with a lithium ion when an electrodemanufacturing process is performed in the electrode manufacturingapparatus 100. Herein, there will be exemplified a roll-shaped electrodesheet to be used to manufacture a negative electrode of a lithium ionsecondary battery.

By way of example, a lithium ion secondary battery is formed by stackinga positive electrode and a negative electrode with a separatorinterposed therebetween to be accommodated in a battery case andimplanting an electrolyte therein. Each of these positive and negativeelectrodes is manufactured by previously cutting a roll-shaped electrodesheet into a piece having a length or shape as required.

In the present example embodiment, a roll-shaped electrode sheet of anegative pole is manufactured by doping an electrode material on theroll-shaped electrode sheet W with a lithium ion and winding theelectrode sheet into a roll shape again. In accordance with the presentexample embodiment, as the roll-shaped electrode sheet W which is notyet doped with a lithium ion, for example, as depicted in FIG. 3, a basesheet which is made of a resin or metal and on which the carbon materialC as an electrode material is formed to be equi-spaced from each othermay be used.

Herein, the carbon material C may be graphite, activated carbon, softcarbon (graphitization-easy carbonaceous material), hard carbon(graphitization-resistant carbonaceous material), or the like, butherein, activated carbon, as the carbon material C, having a highercapacity than graphite is used. Further, an electrode material to bedoped with a lithium ion is not limited to these carbon materials, andmay include silicon or compounds containing silicon, or tin or compoundscontaining tin.

(Electrode Manufacturing Process)

Hereinafter, there will be explained an electrode manufacturing process(method) for manufacturing a roll-shaped electrode sheet of a negativepole for the lithium ion secondary battery with reference to theaccompanying drawings. In the electrode manufacturing process, theelectrode sheet W on which the carbon material C is formed is doped witha lithium ion by using the electrode manufacturing apparatus 100 inaccordance with the present example embodiment. The control unit 300controls the respective components of the electrode manufacturingapparatus 100 based on a preset program to perform a doping process.FIG. 4 is a flow chart illustrating an example of an electrodemanufacturing process in accordance with the present example embodiment.

The electrode manufacturing process (doping process) is started bysetting the roll-shaped electrode sheet W in the electrode manufacturingapparatus 100 and pressing a process start button provided in, forexample, the manipulation unit 310. To be specific, a roll core R of theroll-shaped electrode sheet W is inserted and fixed to the unwindingshaft 112A, and the electrode sheet W is unwound and extended on therespective guide rollers 102A, 202A, 202B, and 102B and then wound on aroller core R set on the winding shaft 112B. By pressing the processstart button, the process is started.

When the electrode manufacturing process is started, at block S110(Depressurize Processing Chamber and Accommodation Chambers WhileIntroducing Rare Gases), the control unit 300 exhausts and depressurizesthe processing chamber 200 and the accommodation chambers 110A and 110Bwhile introducing rare gases thereinto. To be specific, rare gases aresupplied from the rare gas supply sources 132A and 132B into theaccommodation chambers 110A and 110B at preset flow rates, respectively,and a rare gas is supplied from the rare gas supply source 232 into theprocessing chamber 200 at a preset flow rate. Herein, as the rare gases,an argon gas is used.

When the processing chamber 200 and the accommodation chambers 110A and110B are depressurized, the insides of the accommodation chambers 110Aand 110B are exhausted by operating the exhaust devices 120A and 120B,respectively, and the inside of the processing chamber 200 is exhaustedby operating the exhaust device 220. Thus, each chamber is depressurizedto a preset vacuum level. Processing may proceed from block S110 toblock S120.

Then, at block S120 (Determine whether Each Chamber Has Preset PressureLevel), it is determined whether or not the processing chamber 200 andthe accommodation chambers 110A and 110B have preset pressure levels(vacuum levels). To be specific, each pressure in the chambers ismonitored by, for example, a non-illustrated pressure sensor. Theprocessing chamber 200 is depressurized to a preset pressure level ofabout 100 Torr, and the respective accommodation chambers 110A and 1106are depressurized to pressure levels higher than the pressure level ofthe processing chamber 200. Processing may proceed from block S120 toblock S130.

If it is determined that the processing chamber 200 and theaccommodation chambers 110A and 1106 have the preset pressure levels atblock S120, the respective exhaust devices 120A, 120B, and 220 arecontrolled to maintain such preset pressures. Then, at block S130 (StartUnwinding and Winding of Electrode Sheet), unwinding and winding of theelectrode sheet W is started.

To be specific, the motors 114A and 114B are operated to rotate theunwinding shaft 112A and the winding shaft 112B such that theroll-shaped electrode sheet W is unwound from the unwinding-sideaccommodation chamber 110A and passes through the processing chamber200, and then, is wound on the winding shaft 112B of the winding-sideaccommodation chamber 110B. Thus, the electrode sheet W is transferredalong the direction indicated by the arrow of FIG. 1. Processing mayproceed from block S130 to block S140.

Then, at block S140 (Spray Lithium-containing Powder toward CarbonMaterial While Supplying Heated Rare Gas), when the electrode sheet Wpasses through the processing chamber 200, a lithium ion is doped on thecarbon material C. To be specific, while a rare gas heated in theheating gas supply unit 260 is supplied onto the carbon material C ofthe electrode sheet W, lithium-containing powder together with a raregas is sprayed from the lithium-containing powder supply unit 250.

In this way, lithium is doped onto the carbon material C of theelectrode sheet W at a high speed. Then, the electrode sheet W after thedoping process is wound on the winding shaft 112B without being exposedto the air.

Further, when the doping process is performed, a discharge speed of thelithium-containing powder from the lithium-containing powder supply unit250 and a discharge speed of the heating gas from the heating gas supplyunit 260 can be respectively adjusted by controlling flow rates of therare gases with the mass flow controllers (MFC) 235.

Furthermore, a heating temperature of the rare gas discharged from theheating gas supply unit 260 can be adjusted by controlling a settemperature of the heater 264. Herein, desirably, the set temperaturemay be at least a temperature at which lithium can be melted, i.e. aboutthe melting point of lithium (about 180° C.). However, in order tosuppress ignition of lithium, the set temperature is lower than theboiling point of lithium (about 1347° C.). Herein, a set temperature ofthe heater 264 of each heating gas supply unit 260 is, for example,about 200° C.

Further, if a slight temperature difference occurs in the processingchamber 200 due to the large width of the electrode sheet W, a settemperature of the heater 264 of each heating gas supply unit 260 may beadjusted separately in order to correct the difference.

Furthermore, a thickness of the lithium film formed on the carbonmaterial C can be controlled by adjusting an amount of thelithium-containing powder or a flow rate of the rare gas supplied fromthe lithium-containing powder supply unit 250. Moreover, a thickness ofthe lithium film can be controlled by adjusting a transfer speed of theelectrode sheet W. By way of example, in order to increase a thicknessof the lithium film, a transfer speed of the electrode sheet W isdecreased, and in order to decrease a thickness of the lithium film, atransfer speed of the electrode sheet W is increased.

Further, by repeating forward rotation and reverse rotation of theelectrode sheet W in a range of the carbon material C, a thickness ofthe lithium film can be controlled. Accordingly, a thickness of thelithium film can be controlled depending on the number of repetition offorward rotation and reverse rotation of the electrode sheet W.Processing may proceed from block S140 to block S150.

Then, at block S150 (Determine whether Winding of Electrode Sheet IsEnded), it is determined whether or not the winding of the electrodesheet W is ended. Whether or not the winding of the electrode sheet W isended may be determined by detecting a wound diameter of the electrodesheet W with, for example, a non-illustrated wound diameter sensor ormay be determined based on a change in torque output of the motor 114Bconfigured to rotate the winding shaft 112B. Processing may proceed fromblock S150 to block S160.

If it is determined that the winding of the electrode sheet W is endedat block S150, rotation of the unwinding shaft 112A and the windingshaft 112B is stopped. Then, at block S160 (Stop Unwinding and Windingof Electrode Sheet), the winding and unwinding of the electrode sheet Wis stopped. Processing may proceed from block S160 to block S170. Atblock S170 (Return Pressures inside of Processing Chamber andAccommodation Chambers back to Atmospheric Pressure and StopIntroduction of Rare gases), the pressures inside of the processingchamber 200 and the accommodation chambers 110A and 110B are returnedback to the atmospheric pressure and introduction of the rare gases intothe processing chamber 200 and the accommodation chambers 110A and 110Bis stopped. When the returning to the atmospheric pressure is completed,the processed roll-shaped electrode sheet W as depicted in FIG. 1 can betaken out.

Thus, in the electrode manufacturing process by the electrodemanufacturing apparatus 100 in accordance with the present exampleembodiment, since a lithium thin film is formed on an electrode materialof the electrode sheet W while lithium-containing powder is melted andsprayed, the lithium thin film can be formed at a high speed. Therefore,a time for doping a carbon material with a lithium ion can be remarkablyreduced as compared with a conventional method in which a carbonmaterial is doped with a lithium ion in an electrolyte. Further, it ispossible to cope with various shapes of a lithium ion capacitor.

Further, in the present example embodiment, the lithium thin film isformed by the thermal spraying of lithium. Therefore, even if anelectrode material is not formed in a sheet shape (plane shape) asexemplified in the present example embodiment, any kind of shape (forexample, three-dimensional shape) of the electrode material can be dopedwith a lithium ion.

Furthermore, the lithium-containing powder used in the present exampleembodiment is stable in the atmosphere to be easy to handle. However,lithium is highly reactive and highly likely to be spontaneously ignitedin the air to be difficult to handle. In this regard, in the presentexample embodiment, outside the electrode manufacturing apparatus 100,the stable lithium-containing powder is handled, and during a dopingprocess, the lithium-containing powder is heated and melted in theprocessing chamber 200 under a rare gas atmosphere. Accordingly, thelithium film can be formed without being spontaneously ignited.

Further, in the present example embodiment, since the lithium-containingpowder discharged from the powder discharge opening 254 through the hole252 of the lithium-containing powder supply unit 250 is heated with theheating gas, it is possible to suppress the lithium from being meltedand deposited at the hole 252 while passing through the hole 252.

Furthermore, in order to suppress the lithium-containing powder fromclogging the hole 252 of the lithium-containing powder supply unit 250,a shaker may be provided. In this case, for example, at the base end ofthe lithium-containing powder supply unit 250, there is provided anairtight hopper configured to temporarily store the lithium-containingpowder and supply the lithium-containing powder to the hole 252 ifnecessary. Here, the hopper may be equipped with a shaker.

FIG. 5 illustrates a configuration example of a hopper equipped with ashaker. A hopper 270 depicted in FIG. 5 includes therein a baffle plate274 that tapers downwardly. At a bottom portion of the baffle plate 274,multiple through holes 276 communicating with the holes 252 are formed.Further, a non-illustrated shutter unit configured to open or close themultiple through holes 276 may be provided. By opening or closing theshutter unit, a timing for discharging lithium-containing powder or anamount of the lithium-containing powder discharged from thelithium-containing powder supply unit 250 may be controlled.

Since the hopper 270 is equipped with a shaker 280, the hole 252 is notclogged with the lithium-containing powder in the hopper 270 by thevibration of the shaker 280, and the lithium-containing power can bedischarged through the powder discharge opening 254. Further, the hopper270 can be detachably attached to the lithium-containing powder supplyunit 250. With this configuration, when the lithium-containing powderdoes not remain in the hopper 270, the lithium-containing powder can besupplied by replacing the hopper 270.

Further, instead of providing the shaker 280 at the hopper 270, astirrer may be provided within the hopper 270. By way of example, asdepicted in FIG. 6, a stirrer 290 may be provided within the hopper 270and rotated by a motor 292. Thus, the lithium-containing powder in thehopper 270 can be stirred and can be discharged through the powderdischarge opening 254 without clogging the hole 252.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

By way of example, in the electrode manufacturing apparatus inaccordance with the present example embodiment, a lithium film is formedon an electrode material formed on a roll-shaped electrode sheet, sothat the electrode material is doped with a lithium ion, but the exampleembodiment is not limited thereto. Further, the electrode material maybe formed on a rectangular electrode sheet. Further, in the electrodemanufacturing apparatus in accordance with the present exampleembodiment, a lithium film can be formed on the electrode materialformed on an electrode sheet having a three-dimensional shape as well asa plane shape. Therefore, such electrode materials can be doped with alithium ion.

The present example embodiment can be applied to an electrodemanufacturing apparatus for a lithium ion capacitor and an electrodemanufacturing method therefor.

We claim:
 1. An apparatus for manufacturing an electrode for a lithiumion capacitor by doping an electrode material on an electrode sheet witha lithium ion, the electrode manufacturing apparatus comprising: aprocessing chamber to and from which the electrode sheet is loaded andunloaded; a rare gas supply unit configured to introduce a rare gas intothe processing chamber; an exhaust device configured to exhaust aninside of the processing chamber to a predetermined vacuum level; and alithium thermal spraying unit configured to dope the electrode materialwith the lithium ion by forming a lithium thin film on the electrodematerial of the electrode sheet loaded into the processing chamber whilemelting and spraying lithium-containing powder, wherein the lithiumthermal spraying unit comprises a lithium-containing powder supply unitconfigured to discharge the lithium-containing powder toward theelectrode material of the electrode sheet; and at least one heating gassupply unit configured to supply a heating gas that melts thelithium-containing powder discharged from the lithium-containing powdersupply unit, and the at least one heating gas supply unit includes aglass pipe, a gas line arranged within the glass pipe, and a heaterwrapping around the gas line, and wherein the electrode sheet is formedin a roll shape, accommodation chambers configured to accommodate theelectrode sheet are respectively provided at both sides of theprocessing chamber to be communicated with each other, and the electrodesheet is unwound in one of the accommodation chambers to pass throughthe processing chamber, and then, is wound in the other accommodationchamber, the lithium thermal spraying unit forms the lithium thin filmon the electrode material while the electrode sheet is unwound andpasses through the processing chamber, the lithium-containing powdersupply unit is a substantially plate-shaped member in which multipleholes are formed, and the plate-shaped member is extended in a widthdirection of the electrode sheet and arranged perpendicularly to theelectrode sheet, and the holes through which the lithium-containingpowder is supplied are arranged in the width direction of the electrodesheet, and the at least one heating gas supply unit is plural in number,and two heating gas supply units are arranged to be symmetrical withrespect to each hole of the lithium-containing powder supply unit in alongitudinal direction of the electrode sheet.
 2. The electrodemanufacturing apparatus of claim 1, wherein the lithium-containingpowder supply unit is provided perpendicularly to the electrodematerial, and the at least one heating gas supply unit is arranged to beinclined to the lithium-containing powder supply unit such that theheating gas is discharged toward a space between a powder dischargeopening of the lithium-containing powder supply unit and the electrodematerial.
 3. The electrode manufacturing apparatus of claim 1, whereinthe electrode material is a carbon material.